/*
* Validate the arch-specific HW Breakpoint register settings
*/
int arch_validate_hwbkpt_settings(struct perf_event *bp,
struct task_struct *tsk)
{
struct arch_hw_breakpoint *info = counter_arch_bp(bp);
unsigned int align;
int ret;
ret = arch_build_bp_info(bp);
if (ret)
return ret;
ret = -EINVAL;
switch (info->len) {
case SH_BREAKPOINT_LEN_1:
align = 0;
break;
case SH_BREAKPOINT_LEN_2:
align = 1;
break;
case SH_BREAKPOINT_LEN_4:
align = 3;
break;
case SH_BREAKPOINT_LEN_8:
align = 7;
break;
default:
return ret;
}
/*
* For kernel-addresses, either the address or symbol name can be
* specified.
*/
if (info->name)
info->address = (unsigned long)kallsyms_lookup_name(info->name);
/*
* Check that the low-order bits of the address are appropriate
* for the alignment implied by len.
*/
if (info->address & align)
return -EINVAL;
/* Check that the virtual address is in the proper range */
if (tsk) {
if (!arch_check_va_in_userspace(info->address, info->len))
return -EFAULT;
} else {
if (!arch_check_va_in_kernelspace(info->address, info->len))
return -EFAULT;
}
return 0;
}
static int __kprobes hw_breakpoint_handler(struct die_args *args)
{
int cpu, i, rc = NOTIFY_STOP;
struct perf_event *bp;
unsigned int cmf, resume_mask;
/*
* Do an early return if none of the channels triggered.
*/
cmf = sh_ubc->triggered_mask();
if (unlikely(!cmf))
return NOTIFY_DONE;
/*
* By default, resume all of the active channels.
*/
resume_mask = sh_ubc->active_mask();
/*
* Disable breakpoints during exception handling.
*/
sh_ubc->disable_all();
cpu = get_cpu();
for (i = 0; i < sh_ubc->num_events; i++) {
unsigned long event_mask = (1 << i);
if (likely(!(cmf & event_mask)))
continue;
/*
* The counter may be concurrently released but that can only
* occur from a call_rcu() path. We can then safely fetch
* the breakpoint, use its callback, touch its counter
* while we are in an rcu_read_lock() path.
*/
rcu_read_lock();
bp = per_cpu(bp_per_reg[i], cpu);
if (bp)
rc = NOTIFY_DONE;
/*
* Reset the condition match flag to denote completion of
* exception handling.
*/
sh_ubc->clear_triggered_mask(event_mask);
/*
* bp can be NULL due to concurrent perf counter
* removing.
*/
if (!bp) {
rcu_read_unlock();
break;
}
/*
* Don't restore the channel if the breakpoint is from
* ptrace, as it always operates in one-shot mode.
*/
if (bp->overflow_handler == ptrace_triggered)
resume_mask &= ~(1 << i);
perf_bp_event(bp, args->regs);
/* Deliver the signal to userspace */
if (arch_check_va_in_userspace(bp->attr.bp_addr,
bp->attr.bp_len)) {
siginfo_t info;
info.si_signo = args->signr;
info.si_errno = notifier_to_errno(rc);
info.si_code = TRAP_HWBKPT;
force_sig_info(args->signr, &info, current);
}
rcu_read_unlock();
}
if (cmf == 0)
rc = NOTIFY_DONE;
sh_ubc->enable_all(resume_mask);
put_cpu();
return rc;
}
/*
* Validate the arch-specific HW Breakpoint register settings
*/
int arch_validate_hwbkpt_settings(struct perf_event *bp,
struct task_struct *tsk)
{
struct arch_hw_breakpoint *info = counter_arch_bp(bp);
unsigned int align;
int ret;
ret = arch_build_bp_info(bp);
if (ret)
return ret;
ret = -EINVAL;
if (info->type == X86_BREAKPOINT_EXECUTE)
/*
* Ptrace-refactoring code
* For now, we'll allow instruction breakpoint only for user-space
* addresses
*/
if ((!arch_check_va_in_userspace(info->address, info->len)) &&
info->len != X86_BREAKPOINT_EXECUTE)
return ret;
switch (info->len) {
case X86_BREAKPOINT_LEN_1:
align = 0;
break;
case X86_BREAKPOINT_LEN_2:
align = 1;
break;
case X86_BREAKPOINT_LEN_4:
align = 3;
break;
#ifdef CONFIG_X86_64
case X86_BREAKPOINT_LEN_8:
align = 7;
break;
#endif
default:
return ret;
}
/*
* For kernel-addresses, either the address or symbol name can be
* specified.
*/
if (info->name)
info->address = (unsigned long)
kallsyms_lookup_name(info->name);
/*
* Check that the low-order bits of the address are appropriate
* for the alignment implied by len.
*/
if (info->address & align)
return -EINVAL;
/* Check that the virtual address is in the proper range */
if (tsk) {
if (!arch_check_va_in_userspace(info->address, info->len))
return -EFAULT;
} else {
if (!arch_check_va_in_kernelspace(info->address, info->len))
return -EFAULT;
}
return 0;
}
